Cytomegalovirus (CMV), a member of the Herpesvirus family, produces serious ocular disease in adults and young infants. CMV is known to infect 1 percent of all human newborn and antibody studies among adults indicate prior CMV infection has occurred in 50 percent to 80 percent of those tested. While CMV infection is usually asymptomatic, alterations in host immune status, chemotherapy for malignancy, or immunosuppression for organ transplant, can result in ocular manifestations of CMV infection. Despite these facts, only one study has been performed investigating ocular consequences of experimental CMV infection in animals. This proposal outlines a pilot project which will investigate several aspects of CMV retinitis using murine cytomegalovirus (MCMV) infection of neonatal and weanling mice. Our objectives include determination of (1) the pathogenesis of MCMV infection of ocular structurs, (2) the effect of route of MCMV inoculation upon infection of ocular structures, (3) the extent of ocular pathologic lesions which develop during MCMV infection of these structures, (4) the effect of age at the time of MCMV infection upon sensitivity to infection and the development of pathologic lesions, and (5) the effect of immune status on the development of infection and pathologic changes. These objectives will be accomplished by establishing MCMV infection of these animals, via either intracranial or intraperiotoneal routes of inoculation, and by assessing infection through use of tissue culture assay and immunofluorescent localization of MCMV antigen in tissues. Histologic sections will be examined for retinal pathology using both light and electron microscopy. Immunosuppression of MCMV infected animals will allow study of the relationship of MCMV latency and reactivation to the appearance of pathologic ocular lesions. These latter studies will be directly applicable to CMV retinitis found in human transplant recipients. The studies proposed here should provide a better experimental model of CMV-induced ocular disease and should therefore provide important new insights into the mechanisms of human ocular disease caused by CMV.